The invention relates to toasters in general, and more particularly to improvements in electric toasters, especially automatic or semiautomatic toasters which can automatically start and/or terminate the toasting of slices of bread, muffins, rolls and/or other edible commodities whose appearance and/or taste is enhanced as a result of heating and/or browning.
Presently known toasters include a first group wherein the toasting chamber has an inlet for admission of commodities to be treated and such inlet also serves as an outlet for treated goods. These toasters are often provided with means for automatically expelling toasted commodities, and more particularly for expelling portions of toasted goods so that the thus exposed portions can be grasped by hand. The toasters of a second group have toasting chambers with an inlet for admission of goods to be toasted and with a discrete outlet for evacuation of freshly toasted goods. If the goods tend to leave the chamber under the action of gravity, the toasters of the second group are provided with blocking devices which prevent the goods from leaving the toasting chamber prior to completion of the toasting operation. The inlet is normally located at the top of the housing and the outlet is located at a level sufficiently below the inlet to ensure that the goods in the chamber will tend to leave the chamber under the action of gravity, i.e., that the freshly toasted goods will automatically leave the housing as soon as permitted by the blocking devices. An advantage of toasters which belong to the just discussed second group is that an entire slice of toast bread or the like can leave the housing of the toaster as soon as the toasting operation is completed, i.e., that the freshly toasted goods do not undergo undesirable additional heating, browning and/or drying. Moreover, crumbs and otherwise configurated particles of toasted commodities tend to leave the toasting chamber by gravity to thus reduce the likelihood of rapid contamination of the interior of the housing.
The sides of the toasting chamber in each of the aforediscussed types of toasters transmit heat. As a rule, the toasting chamber is flanked by grids which can be provided with projections extending into the chamber to reduce the area of contact between the grids and the goods to be toasted. Such grids exhibit serious drawbacks, mainly because they must be provided with large interstices or otherwise configurated openings which permit penetration of heat from the heating elements into the chamber but which also permit bread crumbs and other particulate matter to reach the heating elements behind the grids. The compartments for the heating elements are rapidly contaminated by foreign matter which accumulates at the bottom of each compartment and which is likely to be ignited as soon as the top of the pile of contaminants comes sufficiently close to the heating elements and/or when the temperature in the compartment reaches a certain point. Moreover, the grates are normally permanently installed in the housing so that they cannot be readily cleaned. Still further, the grate bars which actually contact the goods in the toasting chamber leave impressions in the form of darker (charred) strips which affect the appearance of the goods.
The heating elements of presently known toasters are electric resistance heaters, i.e., pieces of normally convoluted metallic wire which emits heat in response to connection in circuit with a source of electrical energy. The cost of making convoluted wire is rather high, and such wires must be mounted on insulators which are then installed in the housing of the toaster. Another drawback of resistance heaters is that a certain interval of time must elapse before they begin to emit heat at a desired maximum rate. Furthermore cooling of such resistance heaters takes up a relatively long interval of time so that heat energy is wasted immediately after the start and also upon completion of a toasting operation, and electric energy is wasted at the start of each such operation. Heat which is radiated by resistance heaters subsequent to their disconnection from the energy source can bring about undesirable additional or extensive toasting of certain commodities, especially if the toasted commodities are not automatically expelled or otherwise evacuated from the toasting chamber.